PeBeKa S.A. bore two mainline tunnels under the Łazienkowska Thoroughfare and seven eastern mainline tunnels between the “Politechnika” and “Marymont” stations, all of them constituting elements of the first line of the Warsaw metro system. The company constructed also additional infrastructure such as small shafts, fan stations, and turnout chambers.

Metro tunnels from B12/13 to B19, Warsaw

Investor: Metro Warszawskie Sp. z o.o.
Time of project execution: 1987 - 2008

Additional technical data:

  • Combined length of the tunnels: 4900 m
  • Diameter inside the support: 5.2 m
  • Used technology: The mining and construction methods with the application of a non-mechanised protective shield

Location

Poland, mazowieckie Province,
Warsaw

Project outline

For PeBeKa, the construction of the Warsaw metro was one of the most important projects related to the construction of transport infrastructure. The executed project constitutes an integral part of the first line of the Warsaw metro with the length of 23 km. In view of the geological conditions, carrying out this task, the company used the forward grouting technique. The mastered and implemented modification of the previously applied shield tunnelling method consists in the chemical consolidation of loose sands. In the crown of a tunnel there occurs a barrier made of chemically consolidated sand which precedes the advance of the shield. This method effectively eliminates uncontrolled slippage of sand into a tunnel.

The most difficult engineering tasks during the construction of the metro line included the building of a shallow pass of the mainline tunnels under the Łazienkowska Thoroughfare. At the depth of just 80 cm under the tarmac surface of the road, PeBeKa bored two mainline tunnels and a technical communication tunnel, each with the length of 88 metres

Greatest challenges

  • Boring the tunnel under the operational cross-city railway line
  • Boring the tunnel under important thoroughfares

Key moment

Boring the metro tunnel just 1.5 m under the operational cross-city railway line.